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Eight members of the Board, the Secretary of the Institute, and eleven guests were present. Vice-president Henry S. Drinker presided. The President was authorized to appoint delegates to a meeting, on May 16, of the League to Enforce Peace. The Joint Conference Committee reported that the American Institute of Metals had accepted the invitation to form the Institute of Metals Division of this Institute. The Committee on Publications of the Institute of Metals was added to the Committee on Publications of the A. I. M. E. Exchange of one volume of Transactions of the A. I. M. E. at reduced price to members of the British Institute of Metals was authorized, in return for the reduced price given to our Institute of Metals Division on the annual proceedings of the British Institute.

Jan 6, 1918

During the past 18 months a rock mechanics project has been in operation at Renison Limited. The project was established to identify and investigate key problem areas that would affect future production at the Renison mine. An in-house approach was adopted, using shall compact equignent, to investigate ground behaviour. Information on the rock stress field was considered to be particularly important for an understanding of ground behaviour. A high horizontal stress component exists, which enables large flat dipping spans of hanging wall to be opened up, with support being provided by post pillars. The amount of support provided by these post pillars has been found to be low.

Jan 1, 1982

By Carl E. Swartz

Although a number of articles appeared during the war advocating the use of cadmium in lead-tin solders, very little information of value can be found in the literature regarding the properties of solders containing cadmium. In most of the published articles the cadmium seems to have been considered merely as a partial substitute for tin in a tin-lead alloy rather than as an essential constituent of a ternary alloy. The primary object of the substitution of cadmium for tin was to lessen the amount of tin required, at a time when the latter was scarce and high-priced, and thus to produce a cheaper solder. While this object was accomplished, the new properties resulting from a change from a binary lead-tin alloy to a ternary lead-tin-cadmium alloy were not given proper consideration in many cases. For the past few years, the American Smelting & Refining Co. has been marketing a very considerable amount of cadmium in the form of lead-tin-cadmium alloys for use as solders for certain special purposes, and the successful use of these solders suggested that if more extensive knowledge were available concerning the properties of lead-tin-cadmium alloys of various compositions their field of usefulness might be materially extended. The investigation described in the present paper was undertaken to obtain this information and, by means of tests under conditions approaching those of practical use, to determine the suitability of cadmium solders for various purposes. Characteristics and Requirements of Solders in General General Physical Properties.—When cast into bars, solder should present a smooth and bright appearance free from oxide inclusions and bubbles. Ductility should be as great as possible without sacrificing tensile strength, and vice versa. Hardness and specific gravity are not of any great importance. Melting Characteristics.—The melting or solidification range is important. This statement applies both to the extent of the range and to the actual temperature at which complete solidification occurs. A rather narrow solidification range is desirable in soft solders in order that solidification may take place quickly. The solder should have high fluidity at temperatures only slightly above its melting range. For a

By D. R. Wilburn

This summary of international mineral exploration activities for 2006 draws upon avail-able information from literature, industry and U.S. Geological Survey (USGS) specialists. The summary provides data on exploration budgets by region and mineral commodity, identifies significant mineral discoveries and areas of mineral exploration, discusses government programs affecting the mineral exploration industry and presents analysis of the mineral industry based upon these data. Two types of information are reported and analyzed in this annual review. They include budgetary statistics provided by Metals Economics Group (MEG) of Halifax, Nova Scotia, and information on regional and site-specific exploration activities that took place in 2006 compiled by the USGS.

Jan 1, 2007

Since the ecrly 1970's several factcrs have changed. In the East the larger tracts of coal mined with large eauipment are being dePleted, The cost of moving the larger equipment from small tract to small tract becomes eccnomicallv unattractive, Conseauently, the tracts are being mined with smal!er draglines or with loader/truck haulage combination, This has resulted in a major increase in the cost of moving a cubic yard of overburden,

Jan 1, 1989

In a previous paper in these Proceedings(l) it was shown from a study of the bore'logs and analyses then available, that the brown coal seams of the Latrobe Valley areas show progressive changes in composition with increase of stratigraphic depth, equivalent to a rise in rank: These changes appear as:(i) An increase in ultimate carbon and hydrogen, calculated on a dry, ash-free basis, and(ii) An increase in calorific value, calculated on the, same basis, each of the order of 1% per 100 ft. of depth, and(iii) A decrease in moisture content of the order of 0.5% to 1.0% per 100 ft. of depth. The decrease in moisture content was found to be less regular than the other changes. In some bores the moisture content remained more or less constant throughout a single seam, or fluctuated slightly, decreasing stepwise on passage to the seam below.It was noted that individual analyses within a bore showed irregular fluctuations, tending to mask the general trend in composition change. This was particularly so for the moisture content, which had been determined for 10 ft. lengths of core, whereas the other components were determined for 50 ft. lengths of core. Averaging of the moisture contents over 50 ft. lengths reduced the masking effects of these irregularities. The suggestion was made that these irregularities arose from variations in the relative proportions of pollen, resin, wood (lignite) and woody attritus composing the core. Such variation in the coal seams has since been established in some detail for the...

Jan 1, 1948

By M. S. Klima, A. P. Pinkerton

Solid-bowl (decanter) centrifuges are used extensively to dewater slurries in a wide range of industries. However, the application of decanters as classification devices is not as common. In this study, the performance of a continuous, pilot-scale, solid-bowl centrifuge was evaluated when classifying an ultrafine coal slurry containing nearly 60% material less than 10µm. The current study examined the effects of operating conditions on centrifuge performance. The test conditions included centrifuge bowl and scroll speeds, volumetric feed rates, solids concentration, and pond depth. Centrifuge performance was evaluated using partition curves, along with product yields and solids concentrations.

Jan 1, 2000

By Jim Frazier

Tradition has often dictated low design load stresses on piles. Such traditions often developed prior to modern static or dynamic pile testing methods and perhaps result from a few limiting situations. These low stress limits were then broadly applied, even in cases where the piles could carry substantially higher loads. With sufficient testing to prove the design, higher design loads may present significant overall savings to the project owner. The cost of the testing then becomes an insignificant cost compared to the potentially great benefit of increased pile loadings. To confirm higher load possibilities for driven piles, the pile is tested either statically or dynamically. Further savings and increased testing efficiency result from remote dynamic pile testing. This paper presents a project where design stresses were considerably increased as a result of additional testing and use of remote dynamic pile testing equipment.

Jan 1, 2002

By S. Budirsky

J.B. Gwiazda's article deals with an interesting problem that has not been studied thoroughly up to now. Gwiazda has proposed a technical solution that eliminates horizontal load imposed by the supports on the roof. That load is due to a discrepancy between the trajectories of the canopy and the overlying strata. It is true that the improved lemniscate guidance system proposed by Gwiazda could eliminate the horizontal load but, on the other hand, it would represent a higher cost of the supports, and it would complicate the already complicated mechanism of powered supports. That is why we must be convinced that the proposed improvement is actually needed. From that point of view, the following questions should be elucidated. As shown in Fig. 1, the point O travels along the curve a, which produces horizontal load on the roof in the direction of the coal face. As stated by Gwiazda, "such a high load is capable of destroying the roof above the support, causing rock debris to be scattered around the face." The results of our measurements carried out in coal mines of the Czechoslovak part of the Upper Silesian Coal Basin show that the convergence in the modern type of powered supports does not exceed several millimeters (not more than 10) per hour. Similar conclusions were drawn from field measurements performed in the Polish part of the Upper Silesian Coal Basin (see S. Romanowicz and H. Szopka in Proceedings, Scientific and Technical Symposium Simmex '85, Katowice, Poland, pp. 73 -83). The small vertical closure of the supports also induces a small horizontal displacement of the canopy. In addition to this, the transmission of forces between the roof and the canopy is influenced by the layer of debris on it, i.e., the canopy slides without imposing a greater horizontal load on the roof. This was deduced from field measurements of Voest-Alpine F 4/4600 powered supports equipped with rams instead of the common front lemniscate links (denoted as 1 in Fig. 5). In these supports, the pressurizing of the space of piston rod (la in Fig. 5) causes the rams to close, which induces horizontal load on the roof in a direction toward the coal face. After the setting of a support unit, the pressure in the piston rod space was found to drop, frequently to zero, because the small horizontal sliding between the canopy and the debris or inside the debris caused the horizontal reaction from the roof to fall to zero, although the debris were pressurized by vertical setting load. As a consequence, there was no horizontal load imposed by the canopy on the roof. A rise of the horizontal load was recorded only after the passage of the shearer and during lowering of the adjacent units. Thorough information on the results of the afore- mentioned field measurement is given in the paper, "Analysis of the performance of shield powered supports installed in a thick seam," published in Mechanizacja i automatyzacja gornictwa, 1982, No. 12, pp. 38-46. An English translation of the paper is available from the author. We have deduced from our observations that horizontal load imposed by the canopy on the roof in the direction toward the coal face is useful for roof control because it limits the displacement of the immediate roof toward the gob particularly during the rise working. We came to the conclusion that horizontal load on the roof toward the coal face should be induced on purpose. Could Mr. Gwiazda prove with the results of field measurements his contrary opinion? Has the small horizontal displacement of the canopy toward the face actually had an adverse effect on the roof? As shown in Fig. 2, during the setting of a support unit, the canopy imposes a horizontal load on the roof in the direction of the gob. In this case, I share Gwiazda's opinion that the horizontal load could have an adverse effect on the roof. Nevertheless, two important circumstances were neglected - the horizontal compliance of the supports and the interaction of adjacent units. The question of the compliance was analyzed precisely by I. Krumnacker in Gluckauf -Forschungshefle, 1984, NO. 5, pp. 219-223. He found that due to the clearance between the hinge pins and the eyes of the sheild and due to the elasticity of the steel structure,

Jan 1, 1988

By Robert G. Ditchburn

Dating seafloor mineralization at hydrothermal centres of submarine arc volcanoes is important for understanding deep-seated volcanic events that can produce deposits rich in base and precious metals. The activity ratios, 228Th/228Ra, 228Ra/226Ra (Bq.Bq-1) and 226Ra/Ba values (Bq.g-1) are used for dating barite- rich seafloor massive sulphide (SMS) in the age ranges 0.3 ? 12 years, 3 ? 35 years and 500 ? 15,000 years, respectively. Thus, the time elapsed to amass an economic deposit and, ultimately, its capacity for sustainable extraction, can be estimated. 226Ra/Ba and 228Ra/226Ra values have been measured in relatively young chimneys that were collected, 1998 to 2006, from hydrothermal sites at Brothers and Clark volcanoes (Kermadec arc) and East Diamante volcano (Mariana arc) to check these initial ratios, essential for calculating ages for older mineralization at the same sites, were not varying significantly. We found that the 226Ra/Ba value for fresh SMS mineralization at the Brothers NW caldera and East Diamante hydrothermal sites have been reasonably stable for 6 years and 2 years, respectively. At both sites, the 228Ra/226Ra value for fresh SMS has been stable for 5 years. This was established from young chimneys where the measured 228Ra/226Ra value could be corrected for radioactive decay using the age derived via the 228Th/228Ra method. However, long-term stability of the initial 226Ra/Ba and 228Ra/226Ra values has yet to be proven. These isotopes of Ra are used as a proxy for better understanding of the transfer of Ba from deep magmas to the seafloor, via the circulating fluids of the hydrothermal system.

Jan 1, 2011

By Robert J. Timko, Charles D. Taylor, Edward D. Thimons, Tom Mal

A test system was developed for measuring airflow in the National Institute for Occupational Safety and Health (NIOSH) ventilation gallery using a three-axis ultrasonic anemometer. The gallery was used to simulate face airflow conditions in underground mines having a blowing curtain. Airflow data collected at multiple sampling locations between the face and the end of the curtain were used to draw airflow profiles for different curtain setback distances, intake flow quantities and entry widths. In addition, methane was released at the face, measured at the sampling locations, and displayed as methane distribution in the area between the curtain and the face. Entry geometry had a significant effect on airflow patterns, and the flow patterns affected the distribution of methane in the entry. Flow measured at and parallel to the face was a good predictor of methane dilution and removal within two feet of the face.

By E. M. Wise

The practice of adding moderate quantities of nickel to a variety of bronzes has been employed by foundrymen for many years with several objects in view. In some instances it was desired to harden the alloy; in others it was to increase the fluidity or to improve the solidity of the castings, or to refine their grain. These important matters have been considered in detail by Pilling and Kihlgrenl and by numerous other workers cited by them, and with the exception of the first will not be considered in the present communication. The possibility of reducing the cost of bronze by replacing a portion of the tin with nickel received attention some years ago by Burgess and Woodward12 and, as will be shown later, offers attractive savings in cost under present conditions. The age-hardening characteristics of the nickel bronzes of appropriate compositions have been known for some time and were mentioned by Price, Grant and Phillips3 and discussed by Wise4 in connection with their paper. These matters are further considered in recent patents15 and are becoming of commercial importance in the production of high-strength castings. The equilibrium relations existing in the high-copper region of the copper-nickel-tin system have been carefully studied by Eash and Upthegrove,6 and in somewhat less detail by Veszelka.7 The observa-

Jan 1, 1934

By W. P. Ward

I desire ho put on record a fact in relation to the effect of man ganese on pig iron which I have never seen in print, and which may, perhaps, not have been observed by anyone except myself. In 1875, while experimenting on the production of ferroman ganese in a blast furnace, I had burdened the furnace with a charge which I calculated would produce a 15-per cent. spiegel. The fur nace was very hot, having been running for a couple of days on a very light burden, and making a burnt iron, preparatory to the experiment I proposed to make to produce a high grade of spiegel. I calculated that the charge would begin to work in the fur nace in about twelve hoars after it was put on. After the -lapse of that time I commenced to watch the furnace carefully, but found little or no change in the appearance of the metal, although there was a very decided change in the cinder, showing that the man ganese ore had come in work. The iron was quite gray and very tough. The character of the cinder was good for a spiegel cinder, and 1 could not imagine where the manganese was going to, as it (lid not appear to be in either metal or cinder in anything like the quan tity indicated by the charge. The next morning things were still in the same condition. The furnace was very hot, the cinder good, and the iron very gray. I was then sorely puzzled. I had never heard of a gray iron with over 4 or 6 per cent. of manganese, and had no notion that an iron with more manganese could be gray and tough. With great difficulty a piece for chemical test was broken from a pig. Not less than a hundred blows from a heavy sledge were required to break it off, I took the specimen to the shop and directed that some borings from it should be brought to the laboratory, as soon as possible, whither I myself at once repaired to put things in readi ness for a rapid manganese determination. In about half an hour the machinist came in with the iron specimen in one hand and about a dozen blunted and broken steel drills in the other, saying that it mas impossible to drill the iron. There were several little depressions in the iron, which was malleable enough to be indented by the point of the drill, but not a chip had been cut from it. The metal was never subjected to further physical tests. A chip broken from

Jan 1, 1882

The one hundred and twentieth meeting of the Institute was held at Chicago, Sept. 22 to 26, inclusive, and was in every way success although the steel strike against the United States Steel Corpn. prevented many engineers from attending the steel session and made necessary the annulment of the trip to the steel works at Gary on Tuesday. All of the meetings were held at the Congress Hotel, with the excep-tion of the session on Non-ferrous Metallurgy which was held at the Coliseum where the Fifth National Exposition of Chemical Industries was in progress. This session was a joint one with the American Electro-chemical Society. The total attendance, as shown by the registration, was 850.

Jan 11, 1919

By M. P. Board, M. J. Reus

Instrumentation was installed during construction of the Silver Shaft in northern Idaho to evaluate lining behavior and rock deformation. Rock mass displacements were monitored with multiple-position borehole extensometers. Liner stress and strain were measured with concrete pressure cells and embedment strain gages. Rock displacement data from the 5,955-ft level indicate rock mass anisotropy. Liner stress and strain data reflect high in situ stresses and nearby station and raise construction. Continued monitoring and preliminary analysis indicate that concrete-lined, circular shafts are stable for high, unequal stress fields and anisotropy in deep level mines.

Jan 1, 1984

By J J. Frausto, G R. Ballantyne, M S. Powell, R Cruz, K Runge

Hydrocyclones are the most widely used device for classification in a grinding circuit. However, even the most efficient hydrocyclone has a bypass of fines from the feed to the underflow which reduces comminution circuit performance, as well as misclassification around the cut point. Fine screens classify only according to the particle size, allowing for a reduction in the recirculation of fines back to the mill. The development of high capacity multi-screens makes fine classification in a grinding circuit a viable option. Minera Saucito recently substituted hydrocyclones with screens in its grinding circuit. The change of classifier resulted in an increase in throughput and lead recovery but a decrease in silver recovery. This case study presents the changes in comminution and flotation performance that occurred after the installation of screens and uses historical operational data collected over 12 months of operation to investigate the reasons for these observed changes. CITATION:Frausto, J J, Ballantyne, G R, Runge, K, Powell, M S and Cruz, R, 2017., in Proceedings MetPlant 2017, pp 298–314 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 11, 2017

The Annual Business Meeting of the members of The Rocky Mountain Coal Mining Institute held during he 84th Regular Meeting of the Institute was called to order by the president, H. Dean Jacot at 11:30 a.m Tuesday, June 28. 1988 in Peak Room 5 of Beaver Run Resort at Breckenridge, Colorado. Twenty three were present and a quorum was established. The president stated the purpose of the annual meeting is to inform members of the status of the affairs and activities of the corporation during the year. It was moved by Loren Linville, seconded and carried to approve the minutes of the previous meeting as published in the 1987 Proceedings. The chair called for reports of the various com¬mittees and these reports will he placed on file in the RMCMI office. Bylaws and Resolutions. Chairman Loren V. Linville reported there were no bylaws revisions. He further reported that the Board had adopted two resolutions: (I) Noting the passing of members since the last convention-Richard T. Brownrigg. Don A Dewey, John T. Maulshy. Hugh D. Nyquist and Mike Zakotnik. (2) Recognizing the superior skills of J. Brett Harvey. RMCMI Vice President of Utah. For recruiting 26 new members from the State of Utah and named him as #1 Recruiter in the Institute?s 1988 membership drive. Linville further commended the Executive Secretary officers, chairmen and committees loran excellent job in planning the 84th Regular Meeting and convention. Membership. In the absence of chairman Ed Sullivan. the secretary reported there are currently 718 active or dues paying members, 51 Life Members and 250 delinquent in dues payment. In the 1988 membership drive. 132 new members have been recruited and 74 of them attended this convention making up 27V, of the total attendance. Patrons of the Institute. This report was given by the secretary for chairman Ira McKeever. A total of 124 plaques has been prepared during the low year life of the program. It has been culled to 119 possible donors as some firms have gone out of business or consolidated. Of this number 46 renewed their annual $100 donation and three new Patrons have joined prior to the convention for a total of 49. During the convention. four new Patrons donated $100 each. tour former Patrons pledged $100 each and seven would be-new Patrons pledged $100 each for a total of 15. This would bring the grand total to 64 if all pledges are received prior to the close of this fiscal year as opposed to 59 renewals in 1987. Program. Co-Chairman Pete Nielsen announced the convention program theme "Broadening OUR Horizons" was well received despite the loss of three speakers during the final days prior to convention. Because the remarks of the Monday luncheon keynote speaker ran over the first time-to-be-tried Monday afternoon Poster Session was delayed almost an hour in beginning. This well thought out feature will he run again next year but in a different time frame. Nielsen thanked his co-chairmen, Bill Balaz and the Poster Session chairman Marcie Greenberg. Publicity. Chairman Tom Egan reported three newsletters including the convention newspaper were sent members during the year. He and Bob Jacob of Bob Jacob Public Relations were at registration daily to secure business card ads and to solicit advertising for the Proceedings. Scholarship. Chairman Keith McGinnis reported that six of the seven scholarship recipients were present at the convention. The University of Arizona at Tucson was added this year and it was the only university visited this year by the chairman. Each scholarship recipient was introduced to the membership at the Monday morning Welcome Session, presented a plaque and responded. The input Iron each winner was most favorable to the program. Each was appreciative of the many contacts made and the educational seminars and programs. McGinnis noted that the mining engineering department at the University of Wyoming may be dropped during the coming year. Joe Dunlap suggested that every member rally support of this department. Scholarship Award Winners: (top) Christine Gorrell-WY, Brian Memmott-UT and Andrew Kuchera-ND. (bottom) Anthony Bowler-AZ, LaVerne West-NM and Steve Newman-MT. Convention Committees Arrangements. Doris Finnie presented the following report: "In addition to the usual arrangements for this or any convention, there were others made for Special Events which included a Sunday historical tour and luncheon for 40, a Monday morning fashion show attended by 70 women. an afternoon scarf tying program for 47 with RMCMI red

Jan 1, 1988

The petition for the formation of a Tulsa Section was granted. The final budget for the year 1917, and the tentative budget for the year 1918, were adopted. The Secretary was instructed to continue to send the Bulletin to all members whose dues have been remitted on account of their being in the war service, but to hold the Transactions and send them on request to the address furnished for the purpose. The issues of the Bulletin were presented to the Federal Fuel Administration, at its request, with the compliments of the Institute. Fifty-nine Members, five Associates, and fifteen Junior Members were elected. The resignation of one member was accepted. The clues of four members who are on active duty at the front were remitted. An extension of time for the payment of clues was granted to four members, upon request.

Jan 2, 1918

This paper describes the behaviour, under creep conditions, of a cast lead creep specimen consisting of five crystals, the boundaries of these crystals being substantially at right angles to the direction' of tension, i.e., across the long axis of the specimen. This particular specimen was obtained in an attempt to produce a single crystal in the manner described in the appendix of a previous paper (1).Thus, the specimen was of the same shape and size, was composed of the same purity lead and received the same preliminary treatment as the single crystal test-pieces.The object of the experiment was mainly to observe the effect of the crystal boundaries on both the deformation of the test piece and the process of recrystallisation and to compare the creep rate of the test-piece with that of a specimen consisting of one crystal only.EXPERIMENTAL METHODThe specimen had an effective test length of 10 cms. and a cross $ection of 0·5 in. x 0·25 in. In Fig. 1 is given a sketch of the specimen to scale showing the positions of the crystal boundaries on all four surfaces. Except for those of crystal No. 4, which was confined to approximately one-half the cross section of the specimen, the boundaries of each crystal traversed the four faces.The specimen was mounted in exactly the same manner as the single crystal specimens. During the creep test, it...

Jan 1, 1941

Fine coal is defined as material with a maximum size of 1/2 in. Various methods for separate washing of such coal are discussed briefly because separate treatment can lead to a higher overall recovery of coal or to a product having a lower ash content.A felspar jig is discussed in detail because it is the method most recently adopted in Australia, and because it has the advantages of compactness, flexibility and automatic Gontrol, with minimum operator attention. This jig has a variety of adjustable controls to enable the desired results to be obtained from a wide range of coals and the general application of each control is discussed.The only separate treatment of fine coal in the Illawarra district is by felspar jigs on Bulli seam coal.INTRODUCTIONAll reasonably large Australian collieries now win coal by mechanical methods. but while mechanization leads to more economic production of high tonnages, it also changes the characteristics of the coal won. In particular there is an increased proportion of fines, and an increased ash and moisture content. However, specifications of coal for sale have become more stringent, and consumers now require coals in a definite size range with a lower and more uniform ash content, as well as with a low and uniform moisturecontent.These factors have led to the need to wash and grade run-of-mine coal at the pithead. In' plants where the whole of the run-of-mine coal is treated in a jig, some of the fine coal in the feed is beneficiated; the extent depending on factors such as the type of coal and the feed rate. However, for dense medium treatment, fine coal must first be screened out, and there may then be no washing of fine coal at all.

Jan 1, 1961